The present invention is directed to a method and apparatus for improving the quality of an image that is developed by a liquid carrier.
More specifically, images developed onto, transferred to, or written on paper and other output substrates by processes using liquid inks are known to leave liquid carrier in addition to small particulates comprising the image on that substrate. This residual fluid left in the image or paper is objectionable for a number of reasons: the carrier fluid is expensive and reuse is desirable; the carrier fluid may lend an objectionable feel or odor to the output print; the carrier fluid may present some level of health hazard. For these reasons it is necessary to remove the fluid, i.e., dry the print. Present methods of drying the fluid include, but are not limited to, evaporation of the fluid by application of a flux of hot air laterally over the surface; application of heat to the surface; removing the fluid via capillary action by contacting a material with small pores that wet easily by the fluid (i.e., blotting); wiping the surface with a low pressure blade, etc. In addition, it is possible to try to remove fluid from the particulate image by applying a pressure gradient across the image and substrate by either blowing or sucking normal to the surface.
These methods typically work well for removing the liquid carrier from the free surface of the image. The degree of success or rapidity of success decreases as the thickness of the particulate image increases. Fluid deep in the image is held by surface tension forces, and moves to the surface slowly, or not at all. This may necessitate lengthy drying processes that are undesirable for rapid process speed or for compact process hardware.
A need currently exits for a method of moving fluid carrier from within the particulate image to the surface, where other processes exist to remove it, as discussed above.
Cross reference is made to the following applications filed concurrently herewith: Ser. No. 09/699,862 entitled xe2x80x9cMethod For Improving Oil Recovery Using An Ultrasound Techniquexe2x80x9d, 09/699,871 entitled xe2x80x9cA Method For Removing Trapped Impurity Aggregates From A Filterxe2x80x9d, 09/699,804 entitled xe2x80x9cMethod for Dispersing Red And White Blood Cellsxe2x80x9d, Ser. No. 699,882 entitled xe2x80x9cAn Ultrasonic Method For Improving Cleaning And Redispersal Of Saturated Particle Aggregates In Processes Using Liquid Inksxe2x80x9d, Ser. No. 09/699,939 entitled xe2x80x9cMethod For Manufacturing Processxe2x80x9d, and Ser. No. 09/699,703 entitled xe2x80x9cProcess and Apparatus for Obtaining Ink Dispersions by Subjecting the Liquid Inks to an Ultrasonic or Sonic Signalxe2x80x9d.
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In accordance with the present invention, there is provided a method for drying a porous solid saturated with a fluid including the steps of subjecting the saturate porous image to an ultrasonic signal to release the fluid from the saturated porous image layer; removing the fluid from said saturated porous solid, said subjecting step includes applying a predefined acoustic slow wave frequency based upon the particle sizes in said porous image layer thereby causing the fluid to move from an interior of said porous particulate image to an outer surface of said porous image, where fluid can be removed by conventional image.